1. Field of the invention
The present invention relates to an inflatable air mattress used to improve the comfort of patients that are immobilized over long periods of time. The mattress of the invention can be used as such or be placed over the mattress of a conventional hospital bed and it is independent from it.
2. Description of the prior art
For this type of patients, it is recommended to provide a mattress which is quite flexible throughout its length to prevent the creation of pressure points on parts of the patient's body that support its weight. These pressure points tend to cause occlusion of blood capillaries on the surface of the skin resulting in the development of body sores or skin rashes. The patent literature is replete with suggestions of mattress constructions intended to prevent this problem. While all of them seem to be based on the use of air inflatable mattresses, a very large number are more specifically adapting the principle of creating a ripple effect on the surface of the mattress, and consequently on the patient's body, to activate blood circulation. However, the known mattresses are quite complex in structure because of the presence of individual air circuits that are separately and alternatively supplied with pressure air and because of the complicated mechanical and electrical control system that is required to operate the mattress properly. These mattresses are consequently extremely costly.
Patents known to the present applicants and addressing this subject are as follows:
______________________________________ U. S. Pat. Nos. 945,234 Hinsdale 3,303,518 Ingram 3,644,950 Linsay 3,653,083 Lapidus 3,674,019 Grant 3,678,520 Evans 3,778,851 Howorth 3,822,425 Scales 3,879,776 Solen 4,193,149 Welch 4,224,706 Young et al 4,225,989 Corbett et al 4,297,755 Mollura 4,346,489 McMullan 4,394,784 Swenson et al 4,525,885 Hunt et al 4,542,547 Sato 4,617,690 Grebe 4,638,519 Hess 4,686,722 Swart U. K. Patents 1,273,342 Hopkins 1,545,806 Hopkins ______________________________________